Ion-doped rare earth oxysulfides having the general formula of Re2O2S:Ln are known, in which Re is a rare earth element and Ln is a doping ion. The doping ion may also be selected from at least one element of Pr, Ce, Eu, Tb, Yb, Dy, Sm, Ho, Tm, Dy and Er. Ceramic scintillators have many advantages over traditional scintillation monocrystals such as CsI, CdWO4 and the like, including high density, high light yield, stable chemical properties, simple preparation process, and no dissociation during processing. Accordingly, they would be scintillator materials with desired and excellent comprehensive performances for radiation inspection instruments or detectors such as X-ray CT, high-speed X-ray scanners, and security inspection equipments. The Pr and/or Ce ion-doped GOS scintillation ceramics have extremely low afterglow, thereby being an ideal scintillator for CT radiation detectors.
In general, the preparation processes of GOS scintillation ceramics include uniaxial hot pressing process and hot isostatic pressing process. The hot isostatic pressing process comprises the steps of directly charging scintillation powders in a metal vessel, and placing the metal vessel in a gas pressure furnace to conduct hot isostatic pressing sintering, which process is very difficult. The uniaxial hot pressing process requires scintillation powders having small particle size to obtain high surface activity, and generally it would be required that the powders have a surface activity of at least BET 10 m2/g.